Marine Pulse Rectifier

The PSS-PRU-MS pulse rectifier is a powerful device │ cathodic protection station for powering an integrated system for providing active cathodic corrosion protection: piers and berths, offshore oil and gas production platforms, floating power plants, large floating structures; as well as the underwater part of the hulls of ships and vessels, including ice class.

A 45 kW inverter rectifier of cathodic protection of the PSS-PRU-MS type based on switching power sources — an external current source in the cathodic protection system — a high-tech cathodic protection station │ CP power supply.

It is used for active cathodic corrosion protection of marine infrastructure facilities:

• Bases of piers, ports, docks, berthing facilities;
• Oil and gas production platforms of various types
• Large floating structures │ floating power plants;
• Metal storage tanks;
• Pile foundations from screw piles │pile grillings on railway piles;
• The underwater part of the hulls of ships and vessels, including ice class.
• In addition to the main purpose, the rectifier can be used as a direct current source in any other technological processes.

Advantages

The high power of the station — up to 50 kW on request — is the optimal solution for large offshore facilities.
Three independent channels of 15 kW each — 3 autonomous stations in one building make it possible to protect 3 objects or 1 large one.
EFFICIENCY │ Efficiency factor — at least 85% — energy efficiency and efficiency of the rectifier │CP power supply.
Automatic operation with minimal maintenance costs.
Overload protection for output power, as well as protection of the device from overheating by means of forced cooling.
There is a version with a digital control unit.
The rectifier can be operated both offline and remotely.
The device with intelligent control provides protection against abnormal situations: breakage of the measuring chain of the reference electrodes, unauthorized access, etc.
PSS-PRU-MS with a capacity of 45 kW is recommended for indoor installation.
Degree of protection IP23.
Possibility of production and customization of equipment according to customer requirements.

Operation Principles

The PSS-PRU-MS cathodic protection rectifier is based on high-frequency pulse rectifiers. Converts alternating current into direct current and supplies the desired potential to the protected elements, suppressing corrosion processes.

They are operated in the cathodic protection circuit according to the principle of operation of the cathodic protection system by the superimposed current method. The method is based on shifting the potential of the steel casing of the hull of a marine structure in the negative direction until the chemical non-reactivity of the metal or its thermodynamic stability is achieved. → Anodes are installed on the underwater part of the metal structure, to which a constant electric current is supplied from external power sources, going to the cathodic polarization of the metal surface → The underwater part of the housing becomes one large cathode and under the influence of polarization, the potential of the metal surface shifts in the negative direction to protective values.

The key characteristic of the system is the possibility of automatic fixation of the electric potential on the surface of the protected object and a corresponding increase or decrease in the output current from the anode. Thus, the object receives a constant optimal level of protection.

The electric potential is fixed by control silver chloride electrodes located between the anodes, where the lowest potential should be.
The data is captured by the reference electrodes and transmitted back to the PRU control panel. The rectifier, in turn, automatically adjusts the output current from the anode.
Thus, the cathode system suppresses and neutralizes corrosion processes on a submerged object.

All parameters of the rectifier │ CP power supply are determined during the development of the cathodic protection project.

Functionality

• Provision of polarization potential measurement;
• Operation in the mode of automatic maintenance of the total or polarization potential at a given level;
• Operation in the mode of automatic stabilization of the protective current;
• Operation in the mode of automatic stabilization of the output voltage;
• Alarm about the occurrence of a break in the circuit of the reference electrode or potential sensor with automatic transition to the output current stabilization mode, at the level that was before the occurrence of an emergency situation;
• Autofixation and indication of the time when the structure is under cathodic protection;
• Short circuit protection in the load circuit with automatic switching to operating mode after the short circuit is eliminated;
• Overload, overvoltage, overheating protection;
• Automatic activation in the preset mode when the supply voltage disappears and resumes (in case of power outages);
• Full information about the output data, operating mode, and other parameters of the rectifier is displayed on the LED display;
• Telemetry type T2 – rectifier control via RS-485 interface "Modbus RTU".
• Calculation and indication of the time when the rectifier is under the voltage of the supply network in the switched-on state.